In the dry cleaning process, clothing or other fabrics to be cleaned are contacted with a solvent that removes dirt, oil and other substances from the clothing. This is a method of removing substances that are on fabrics that are not amenable to removal with aqueous based cleaning detergents. After cleaning the clothing and/or fabrics, the solvent is processed to remove the contaminants that were removed from the clothing, such that the solvent is recycled.
A prominent dry cleaning solvent is perchloroethylene. However, perchloroethylene is an environmental and health hazard, and therefore substitute solvents have been developed for use in the dry cleaning process. There has been increasing pressure on the Dry Cleaning industry to use alternatives to perchloroethylene, that are more environmentally friendly. This has led to the development of new dry cleaning solvents, such as one group of solvents based on silicone, or siloxanes. One particular solvent which has been developed by General Electric is decamethylcyclopentasiloxane, also known as D5. In addition, the new solvent delivers superior fabric quality. This has led to the conversion of about 400 dry cleaning sites from perchloroethylene to the solvent D5.
Today, D5 solvent recovery systems typically use a batch-mode distillation process to purify the solvent. The distillation process is expensive and requires daily, manual intervention to clean the bottom of the distillation apparatus. Improvements in the methods of purifying and recycling cleaning solvents can save energy and money.